0 or more exactly:
Our friends, that is to say our son's friends, will meet us at the airport.
1 said when you want to give further details or be more exact about something:
I'll meet you in the city, that is, I will if the trains are running.
НОВИ ДУМИ
European
May 10, 2021
ДУМАТА НА ДЕНЯ
Shimmer
that is to say ...